Electronic devices use various methods to allow users to provide information to the device and to receive information from the device. Examples of techniques used to provide user input to an electronic device include pressing keys, manipulating a mouse or other tracing input device, using a touch screen with a finger or mechanical stylus, or combinations of these. In certain scenarios, users are more comfortable using convenient and familiar handwriting input techniques to provide input to an electronic device.
Various techniques are used to allow a user to input data into a computer by using handwritten drawings. In one example, touch sensors or other contact location sensors, such a sensors that detect an object in the tip of the stylus, are incorporated into a display screen and the motion of the stylus is tracked by the sensors to determine the movement of the stylus tip. These examples require specialized sensors to be used in the display of screen of the electronic device. These sensors are often susceptible to detecting unintended contact with the display screen, such as when the user rests his or her palm on the display screen when writing thereon. Detecting unintended contact with the display screen occurs with both pressure sensing designs and capacitive touch screens.
Another example of providing handwritten input to electronic devices uses a pen-like device that has an optical sensor in its tip, and this pen-like device is used in conjunction with special paper that has a matrix of dots pre-printed thereon. The optical sensor in the tip of the pen-like device periodically captures images of the paper, and its pre-printed dots, when the pen is writing on the paper and by analyzing changes in the captured images, the motion of the tip of the pen-like device is determined. These motions are accumulated and communicated to an electronic device for further processing. These examples do not support use with conventional electronic graphical displays and are limited to writing images on paper. Writing on paper does not allow a processor to alter or augment the written image as the user is writing. Similar pen-like devices include gyroscopic determination of pen movement instead of optical tracking of surface features. These examples require a more complex design that includes gyroscopic tracking and processing to determine pen movement.
The usability of electronic devices can be improved by providing cost effective designs to allow handwritten user input on a display that can be altered by a processor.